Compact crank therapeutic exerciser for the extremities

ABSTRACT

A compact, portable, therapeutic exercise apparatus and process designed to address the needs of shoulder and knee surgical rehabilitation is disclosed. Specifically provided is a rehabilitative exercise apparatus which comprises a base or pedestal having a vertically disposed main shaft in the form of a telescoping extension projecting longitudinally therefrom, and a crank assembly supported by the main shaft, the crank having length adjustable moment arms. The exercise device enables specific, convenient and expeditious treatment of post surgical knee and shoulder injuries.

[0001] This application claims benefit of U.S. Provisional Application No 60/336,446, filed Nov. 14, 2001, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] (a) Field of the Invention

[0003] The present invention generally relates to an apparatus for post-surgical rehabilitation of orthopedic patients who have undergone reconstruction of the rotator cuff or knee. Through use of immediate controlled post-surgical movement in the instant rehabilitative device, recovery time is significantly reduced and range of motion of an injured limb is quickly recovered.

[0004] Previously, patients were kept immobile for periods of several days to weeks following orthopedic surgery to repair the tendon or cartilage of the shoulder (rotator cuff) labrum or the knee (meniscus). The swelling or edema which resulted from the procedure made movement painful and difficult, and recovery time was extended. Recent advances in surgical procedures and materials make it possible to begin rehabilitation by moving the joint even while the patient is in the recovery room. The affected joint is anesthetized and a rotational movement is induced which substantially reduces inflammation and promotes freedom of movement. As the patient recovers, the exercise is continued, the range of movement and the load being increased steadily.

[0005] The theory is based on on a physiologic model in which a motor program activates muscles in a coordinated sequence to create joint movements that simplify and perform tasks. These programs consist of length dependent patterns which operate at one joint and result in co-contraction coupled forces and a force-dependent pattern which harmonizes motion at several joints, creating coordinated movements using agonist and antagonist force coupled activation to generate force. As applied to the shoulder, together these two patterns result in a motor program of voluntary upper extremity movements. As provided herein, the exerciser not only provides closed chain kinetic exercise which is protective to the glenohumeral joint, and also rehabilitates the scapular muscles of the shoulder.

[0006] Closed chain exercises involving axial loading from distal (hand) to proximal (shoulder joint, scapula) are a more physiologic way of stimulating normal rotator cuff function (Lephart, J., Sports Rehab 1966). Traditional isolated rotator cuff exercises (Therabands) do not integrate muscle activation, potentially creating shears across the joint and are performed in non-physiologic positions. Closed chain rehabilitation exercises can be started in early rehabilitation with the hand fixed below the shoulder level. These exercises rely on motor programs that are specific for sensory and proprioception feedback for integration and activation of the joint.

[0007] The present invention is directed to an exercise apparatus and procedure which is position specific, motion specific and functionally specific, and provides joint integration to enhance postoperative feedback, thus enhancing postsurgical rehabilitation of both the shoulder or the knee. Because the rotator cuff and the knee are systems sensitive to exercise, precise control of movement and of the variation in load are important in the rehabilitation process as is the ability to vary the range of movement through an infinitely variable system of adjustment, not limited to incremental stages. And since the therapeutic system of immediate post-surgical movement must be implemented in the recovery room, a compact device is required which will be usable while the patient is in a hospital bed. The device will also have to be used as recovery continues using a conventional table for support in the case of rotator cuff procedure and with a conventional chair for knee rehabilitation in treatment of the meniscus. Thus, an ongoing and pressing need exists for a simple, portable, robust and cost-effective device designed specifically for knee and shoulder rehabilitation.

[0008] b) Description of the Related Art

[0009] In U.S. Pat. Nos. 5,336,147 (Sweeney) and 5,161,430 (Febey) movable crank devices are disclosed for the exercise of both upper and lower body parts. Both patents disclose equipment effective for general exercise but are not practically functional for post surgical rehabilitation because of their complex, bulky construction and relatively large footprint of use (size and space required) which renders such devices unacceptable in a hospital/post surgical recovery room environment. As an example, the '147 device is directed to the treatment of hamstring muscles requiring both hand and foot pedals, the latter being disposed above the location of a bicycle seat.

[0010] Without making specific reference thereto, the literature and general commerce surrounding the present invention contains disclosures of many different embodiments of exercise equipment useful in changing the pedal radius of hand and/or foot crank pedal machines. However, in all cases such equipment is generally size and space unfriendly to surgical environments, relatively expensive, and of limited versatility. For example, one commercially available piece of equipment is comprised of a large steel body with a built-in seat, handlebars, pedal gear and mechanical resistance system, torque sensing and rate monitoring devices as well as an electronic display system to encourage the user and present performance information, all of which render it unusable in a surgical/rehabilitation setting. Free weights are also commonly used in rehabilitation, however, they are frequently dropped by patients in their compromised condition with consequent injury. Even in a controlled situation with an attendant to assist the patient and prevent such accidents, free weights do not move through a controlled path and depend upon the patient to position and move them through a prescribed and beneficial trajectory, and whose load may diminish to zero at the end of a stroke.

[0011] In accordance with the present invention, a neat, portable, compact, dual moment arm pedal support, cranking system is provided such that an unaffected (undamaged or pain free) arm or leg initially generates the power to move an affected (diminished capacity) limb through a circular stroke of smaller radius, and then by further decreasing the radius for that moment arm of the crank and/or applying greater friction to the central crank axle, subjecting the affected limb to appropriate greater stress in a successful-step healing process. In just one application the crank can be of free rotation (no friction applied to the axle) and by progressively shortening the moment arm of the pedal provided for the affected limb and lengthening that provided for the unaffected limb, the leverage provided to the affected limb is reduced, demanding that it provide more force to overcome the resistance of the system compared to the unaffected limb, whose pedal throw is longer, providing greater leverage and requiring less effort. By manipulation (or co-adjustment) of (1) the lengths of the moment arms of the crank and (2) the friction on the rotational axle of the crank (rotation resistance), harmonized motion of the effected joints can be accomplished and an injured limb can be rehabilitated back to health in a disciplined and prescribed manner.

SUMMARY OF THE INVENTION

[0012] The present invention provides a rehabilitative therapeutic exercise apparatus and process of operating same designed to satisfy the aforementioned needs of shoulder and knee surgical rehabilitation and embodies design features and process steps which avoid the shortcomings of the prior art.

[0013] Specifically disclosed herein is a rehabilitative exercise apparatus which comprises a base or pedestal having a vertically disposed shaft projecting therefrom, a telescoping extension projecting longitudinally therefrom, and a resistance adjustable bearing at the distal portion of the shaft extension. The bearing serves as a support for a crank assembly comprised of a rotatable shaft housed in the bearing and defining a horizontal axis of rotation about the supported bearing. A pair of length adjustable moment arms having pedal or limb support means extending horizontally therefrom are attached to the opposite ends of the rotatable shaft to provide means of reciprocal force leveraging about the crank shaft to effect rotation.

[0014] The vertical shaft bearing is equipped with a clamping member operated by a cam or threaded element so as to provide an infinitely adjustable range of resistance to the rotatable shaft of the crank. The moment arms are comprised of height adjustable telescopic linear assemblies each reciprocally distally attached to the rotatable beam in parallel alignment so as to form a crank about the pivot point created by the rotatable and resistance adjustable support shaft.

[0015] The height to which the vertically disposed shaft may be telescoped to and from the base is controlled by means of a hand operated threaded transverse clamp, permitting the bearing to be fixed at an infinity of locations within the range of the shaft's length. This is important therapeutically to increase the range of movement of the patient over a series of exercise sessions. The crank height will be set at a low setting initially and will be progressively raised as healing progresses.

[0016] As indicated, the rotatable horizontally disposed beam housed by the bearing supports a crank assembly which includes a pair of left and right height adjustable moment arms attached to each end of the rotatable beam and disposed vertical to the beam's horizontal axis. Additionally included in the assembly are a pair of pin elements, grips, or throws attached to each moment arm in parallel axial disposition to the rotational beam axis to provide limb supports in the form of pedals or handles at the distal end opposite the pivot fixed point of the moment arm to the beam. Each adjustable moment arm is comprised of a pair of interrelating male-female elongated members having a telescoping relationship with one another to form a telescoping assembly which can be adjusted in length to provide lesser or greater radii of action in the crank assembly. Fixation of the length of the moment arm can be accomplished by a hand-operated transverse threaded clamp, a pin mechanism or any other means which can set the height of the telescopic moment arm assembly to accommodate any user's rotation tolerance in a particular rehabilitative therapy.

[0017] In a preferred embodiment, the limb support at the distal end of each moment arm is equipped with a rotatable handle or foot pedal having a resilient grip when used by the hand and a non-slip (skid) surface when used by the foot. This rotatable support can be attached to the limb support such as a slideably attached pedal or handle to accommodate different constructions of hand or foot support elements. It is further preferred that any version of handle or pedal be equipped with a quickly-releasable strap to secure the hands or feet to the pedal or handle.

[0018] The base is fabricated of metal or other heavy material to confer balance and stability to the apparatus. As an optional embodiment, the underside of the base is provided with a plurality of fixed open suction cups to permit attachment of the apparatus to a tabletop for use in rotator cuff procedures and to the floor for use in knee procedures a further feature of the present invention is that the outer components of the height adjustable shaft and moment arms can be marked by means of engraving or other permanent technique to facilitate setting to prescribed heights and radii. In each case the height adjusting clamping or pin member is employed as the cursor or moving reference for the user.

[0019] Accordingly, it is an object of the present invention to provide a compact portable rehabilitative exercise apparatus for the rotator cuff and/or the knee which has the capability for shoulder and knee rehabilitation; which allows progressive (competitive) resistance exercising; and provides the capability of working the arm or leg at an infinite number of positions and degrees of resistance. It is a further object of the instant invention to provide a compact, portable exercise apparatus which is usable from a hospital bed with a conventional table or conventional chair; and to provide a portable piece of limb rehabilitative equipment which is competitive in cost and easily affordable. These and other objects and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a perspective view of the exercise apparatus of the present invention from an overhead position.

[0021]FIG. 2 is a perspective view of the exercise apparatus of FIG. 1 from an underside position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] Referring now to the drawings, FIGS. 1 and 2 illustrate an exercise apparatus having a base 1 with an attached vertically arranged shaft 2 in the form of a column. Slidably disposed in shaft column 2 is a telescoping extension member 4 which may be raised to a variety of heights and locked at any of these heights by use of a threaded clamping screw 3. Supported at the uppermost distal end of the extension 4 is a crank assembly having a shaft or beam 5 rotatably mounted through a bearing (not shown) affixed to the telescopic extension 4 and defining horizontal axis of rotation. The crank further comprises a pair of moment arms comprised of male/female portions 6 and 8 each moment arm attached to opposite ends of the rotatable shaft 5, said pair of moment arms having a pair of limb supports 12, each one of the supports being attached perpendicular to the moment arms in a manner so as to generate rotation of the assembly as force is applied to these limb supports 12.

[0023] As can be seen in FIGS. 1 and 2, the preferred embodiment of the invention includes means for selectively varying the distance between the upper portion 4 and the lower portion 2 of the shaft so as to accommodate the particular patient and to adjust stress on the particular limbs. The upper portion 4 of the shaft may be moved vertically to the base 1 so as to increase the height of the shaft and is comprised of an elongated member 4, which has a telescoping relationship with a corresponding elongated member 2 which is attached to and extends vertically from the base 1. There is a hand operated threaded transverse clamp 3 to prevent relative movement of telescoping members 2 and 4. Of course, any type of clamping means may be used to set and stabilized the shaft height as, for example, a pin lock mechanism which is a less preferred means because of the necessary pre-indexing of height of the exerciser.

[0024] Each moment arm of the crank is constructed as an elongated body comprised of elongated members 6 and 8 functionally comprised of upper elongated (female) member 6 having a telescoping relationship with corresponding distally engaged elongated (male) member 8 so as render each moment arm height adjustable to accommodate the recuperative capacities of anyone with a limb injury, dysfunction or problem. As in the case of main telescoping shaft element 4, there is a hand operated threaded transverse clamp 9 to fix and prevent relative movement of telescoping members 6 and 8. And again any type of clamping means may be used to set and stabilized the height of the moment arms (6 and 8) as, for example, a pin lock mechanism. The pin/lock mechanism of course suffers from the disadvantage that it is a pre-indexed measurement of rotational radii and does not possess the sensitivity, flexibility and effectiveness of the preferred embodiment of the instant tool shown in FIGS. 1 and 2.

[0025] To repeat, the particular embodiment of FIGS. 1 and 2 generally demonstrate height adjustable moment arms as hollow male/female assemblies being slidably connected with one another so as to form telescopically extendable distal portions 8 of the arm assemblies. These extendable distal portions 8 may be telescoped to lengthen or shorten the effective length of the crank arms. While a telescoping arrangement is demonstrated in the Figures, other height adjustable moment arm constructions can be appreciated by the skilled artisan such as separately attachable extender pieces.

[0026] Attached near the end portion of each moment arm distal extension 8 are horizontally disposed pins 13 shown only in FIG. 1 to form gripping elements to enable rotation of the crank. Rotatably and slideably mounted to the pins are pedal/handle assemblies 10, the axis of each being parallel to the crankshaft 5 and each shown with finger placement supports. To each pedal/handle 10 is mounted a strap 11 fitted with an adjustment buckle 12.

[0027] The resistance of the apparatus to torque applied by the patient through the crank can be increased and decreased through the use of a resistance adjustment screw 7 mounted at the end of the vertical extension member 4 with its axis coincident and co-linear with the vertical axis of the column 2. Any means of resistance adjustment of the crank can be used within the purview of the invention.

[0028]FIG. 2 illustrates the exercise apparatus showing suction cups 14 used to fix the position of the apparatus to a tabletop or floor. Also shown in this view is the large base to the instant portable exerciser which confers lateral and longitudinal stability through its size. Preferably constructed of metal, the base also enhances stability due its weight. Portability within the purview of the instant invention means a device having maximum cubic dimensions of 2 ft×2 ft×2 ft (6 cubic feet) and a weight not exceeding 40 pounds.

[0029] One of the main features of the present invention concerns the flexibility of the apparatus to accommodate the rehabilitative needs of a wide variety of users and allow for a wide range of resistance and range to promote rapid healing and limit edema and post operative adhesions. A plurality of components of the apparatus are adjustable, permitting the surgeon or therapist to tailor the configuration and resistance of the apparatus to the needs of the patient. Succinctly, the instant portable exercise device exploits a user's limb angular leverage (eg. height/shoulder level), differential moment arm radii, and crank rotational resistance to enforce a disciplined harmonized motion of limb joints.

[0030] The preferred embodiment of the apparatus shown and described herein permits unloaded (no crank rotational bias or height leverage) initial movement of the affected limb with power applied by the unaffected limb. This may be performed at a small radius of action for the affected limb, and an unsymmetrical, larger radius for the unaffected limb. The radius and resistance offered to the affected limb may be increased session-by-session, while the power and radius of movement demanded from the unaffected limb may be decreased correspondingly.

[0031] Succinctly, the instant machine invention provides a means of exercising the upper extremities of the human anatomy by firstly adjusting the lengths of the moment arms of the crank to increase the radii of crank rotation on one extremity to cause a co-contraction of force on the other extremity and a force dependent pattern between the two extremities thereby harmonizing motion at both extremities and rehabilitating any damaged muscles or joints of an extremity. Secondly and relatedly, height adjusting the main shaft below or above shoulder levels to further generate active or passive ranges of rotational motion to create coordinated movements within the shoulder girdle, glenohumeral and upper extremity musculature. The apparatus provides closed chain kinetic exercises that are ultimately protective to the affected anatomical structures. Additional rehabilitative benefit may be derived by raising or lowering the height of the main axis of rotation, the height fixed by means of the clamping screw 3.

[0032] It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims: 

We claim:
 1. An exercise apparatus comprising: (i) a horizontally disposed platform; (ii) a height-adjustable main shaft having one lower end connected in vertical to the platform; (iii) a shaft beam support means perpendicularly disposed to, and housed in the upper end of, the main shaft, said support having means for imposing force to any supported shaft; and (iv) a crank assembly comprised of a crank shaft beam rotatably mounted in said shaft support means to define a central horizontal axis of rotation, said crank assembly further comprising a pair of moment arms each attached to opposite ends of the rotatable beam, said pair of moment arms being height adjustable and each having a pair of limb support elements, each one being attached to the moment arms in a manner so as to generate rotation of the assembly upon application of force to the limb supports, wherein the apparatus operates through manipulation of the main shaft height level, rotational resistance of the crank shaft, and differential moment arm radii to effect a disciplined pattern of harmonized motion of the joints in the limbs of a user.
 2. The exercise apparatus according to claim 1 wherein the moment arms of the crank assembly are comprised of male/female linear assemblies, the female member having means for selectively varying the height of the moment arms.
 3. The exercise apparatus according to claim 2 wherein the linear assemblies of the moment arms have a telescoping relationship with on another so as to vary the length and corresponding height of the elongated arm.
 4. The exercise apparatus according to claim 1 wherein the limb support elements are axially disposed pins parallel to the axis of the rotatable shaft crank support member so as to act as limb handles and support application of force to cause rotation of the crank.
 5. The exercise apparatus according to claim 4 additionally comprising a limb pedestal assembly connected to the axially disposed pins.
 6. The exercise apparatus according to claim 5 in which the limb pedestal assemblies are comprised of limb rest and straplock to provide a secure handle for limbs during operation of the apparatus.
 7. The exercise apparatus according to claim 6 wherein the limb rest is further comprised of finger slots.
 8. The exercise apparatus according to claim 7 wherein the apparatus platform is metal.
 9. The exercise apparatus according to claim 8 wherein the apparatus platform is aluminum.
 10. The exercise apparatus according to claim 8 wherein the apparatus has maximum cubic dimensions of 6 cubic feet and a weight not exceeding 40 pounds.
 11. A method of exercise of upper extremities comprising: a) providing the apparatus of claim 1 in which the verticle height is at or below shoulder levels of a user to generate active or passive ranges of rotational motion to create coordinated movements within the shoulder girdle, glenohumeral and upper extremity musculature in the affected anatomical structures; and b) adjusting the lengths of the moment arms of the crank to cause differential radii in the moment arms of the crank causing greater rotation on one extremity and a co-contraction of force on the other extremity and a force dependent pattern between the two extremities thereby harmonizing motion at both extremities and rehabilitating any damaged muscles or joints of an extremity.
 12. The method of claim 10 wherein the vertical shaft height is above shoulder level.
 13. The method of claim 10 wherein a bias is applied to the rotational crank shaft to increase resistance to crank rotation and to further discipline one shoulder limb vis a vie the other thereby generating a disciplined pattern of motion of the limbs and creating a rehabilitative coordinated movement between them.
 14. A method for exercising limbs in a coordinated sequence comprising: a. providing a portable limb driven crank system having adjustable height, rotational stress, and moment arm length; and (b) manipulating each so as to cause a length dependent pattern of limb motion operating on one joint and results in a co-contraction on the other and harmonizing motion in the joints of both limbs.
 15. The method of claim 13 wherein the limbs are arms and the vertical shaft height is above shoulder level.
 16. The method of claim 13 wherein a bias is applied to the rotational crank shaft to increase resistance to crank rotation and to further discipline one limb vis a vie the other thereby generating a disciplined pattern of motion of the limbs and creating a rehabilitative coordinated movement between them.
 17. The method of claim 13 wherein the limbs are arms.
 18. The method of claim 13 wherein the limbs are feet. 